Mum: The incident, in which Deborah Leonard was allegedly involved, took place during a counselling session (Image: Reuters)

Charges of second-degree murder, kidnapping and gang assault were also brought against church pastor Tiffanie Irwin, 29; Traci Irwin, David Morey, 26, Linda Morey, 54, and Joseph Irwin, 26, who were all congregants at the church; and Sarah Ferguson, 33, the half-sister of Lucas and Christopher, the court document showed.

Tiffanie Irwin and Traci Irwin originally were not charged in the incident, while the other five were initially charged with first-degree manslaughter in Lucas Leonard's death.

Father: Bruce Leonard alleged beat his son inside the "sanctuary room" of a Christian church (Image: Reuters)

An eighth person, church deacon Daniel Irwin, 24, was indicted on charges of second-degree manslaughter, kidnapping and gang assault.

The brothers' mother, Deborah Leonard, 59, will appear in Oneida County Court on December 2.

Charged: Sarah Ferguson is accused of taking part in the fatal beating (Image: Reuters)

She will face separate charges of first-degree assault against Lucas and second-degree assault in Christopher's beating, according to her lawyer Devin Garramone.

Deborah Leonard was initially charged with manslaughter , but Garramone said that charge was dropped.

Attorneys for the other people charged in the case could not be reached for comment.

Christopher Leonard, during a preliminary hearing last month, testified that he and his brother were beaten with an electric extension cord fashioned into a whip.

Arrested: Joseph Irwin is another member of the congregation facing trial (Image: Reuters)

He said Tiffanie Irwin organised the counseling session.

Christopher said he attempted to resuscitate his brother before the boys were loaded into two separate vans.

Group: David Morey is another of the seven people charged in connection with the teen's death (Image: Reuters)

Lucas was transported to St. Luke's hospital in Utica, New York, where he was pronounced dead, prosecutors said.

Most of those indicted in the case remain in jail on bail of tens of thousands of dollars each, while David and Linda Morey have been released on bail of $50,000 (£33,000) each, according to jail records.

Bruce Leonard enters the court room to stand in front of Honorable Judge Bill M. Virkler for a manslaughter charge against him in the death of his 19-year-old son Lucas Leonard, in New Hartford, New York October 16, 2015 (Image: Reuters)